Linux Kernel up to 6.12.69/6.18.9 ALSA loopback_check_format state issue

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.12.69/6.18.9 and classified as critical. The affected element is the function loopback_check_format of the component ALSA. The manipulation leads to state issue. This vulnerability is referenced as CVE-2026-23191. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.69/6.18.9 and classified as critical. This issue affects the function loopback_check_format of the component ALSA. The manipulation with an unknown input leads to a state issue vulnerability. Using CWE to declare the problem leads to CWE-371. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix racy access at PCM trigger The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-23191 since 01/13/2026. The exploitation is known to be difficult. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/19/2026).

The vulnerability scanner Nessus provides a plugin with the ID 299085 (Linux Distros Unpatched Vulnerability : CVE-2026-23191), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.70 or 6.18.10 eliminates this vulnerability. Applying the patch bad15420050db1803767e58756114800cce91ea4/5727ccf9d19ca414cb76d9b647883822e2789c2e/826af7fa62e347464b1b4e0ba2fe19a92438084f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (299085) and EUVD (EUVD-2026-6109). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

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